Numerical simulation of waste heat recovery process from the hot stripped gas in carbon capture process by using ceramic membrane

CO2 chemical absorption process suffers from the high CO2 regeneration heat requirement, so a rich solvent-split mechanism was put forward to recover the waste heat from the hot stripped gas for reducing the regeneration heat consumption. Ceramic membrane-based transport membrane condenser (TMC) can provide a higher heat transfer efficiency, therefore better meet the requirements for waste heat recovery from the hot stripped gas. The ceramic membrane structure is a key factor affecting the heat recovery performance, which has been neglected by previous studies. For investigating the effect of membrane structure, in this study, a condensation and mass transfer model was firstly constructed using the computational fluid dynamics approach to describe the process of waste heat recovery from the hot stripped gas. The errors between the simulated outlet temperature of stripped gas or CO2-rich solvent and the experimental ones are about 1.74 %, indicating the satisfactory accuracy of the model. Based on the model, the effects of ceramic membrane structure and physical parameters on the waste heat recovery performance were comprehensively investigated. The results showed that reducing the wall thickness or inner diameter of ceramic membrane contributes to improving the waste heat recovery efficiency of TMC. Notably, there may be an optimal membrane area beyond which the improvement of waste heat recovery is difficult. Additionally, when the thermal conductivity of ceramic membrane exceeds a critical value (similar to 10 W/(m K) in this study), the improvement of waste heat recovery performance may be difficult only by increasing the thermal conductivity. This study provides an important guidance for the selection of ceramic membranes for waste heat recovery process from the stripped gas in the future.